Dietary sodium, dietary potassium, and systolic blood pressure in US adolescents

Excessive salt intake is associated with hypertension and cardiovascular morbidity. However, identifying those at risk of salt sensitive hypertension (SSH) remains a challenge due to its unequal distribution among populations and inaccurate assessment of dietary sodium (Na) and potassium (K) intake. The objective of this study was to compare indices of dietary Na intake in relation to systolic blood pressure (SBP) in salt sensitive (SS) and salt resistant (SR) subjects from the Dietary Approaches to Stop Hypertension (DASH)-Sodium trial. We hypothesized that when compared to urinary Na or K independently, Na/K ratio is a better predictor of SSH when defined as a 5-10 mmHg change in SBP from low to high dietary Na. Among 404 Black and White subjects, baseline classifications included 177 SS and 227 SR. After diet randomization, on the control 107 were SS and 92 SR and on the DASH 70 were SS and 135 SR. Descriptive statistics, bivariate analysis, followed by linear regression models for baseline and multilevel mixed-effects models after intervention were used to assess the relationship between SBP and dietary Na (as measured by urinary Na/K ratio or Na and K independently) using SS as a categorical factor. SBP was consistently associated with SS, Na/K ratio, and age in all models . At baseline, SBP was significantly higher in SS and SR subjects of the same race and sex, after controlling for age and urinary Na/K ratio and was highest for White females, SS:142.3 (138.8, 145.7) vs. SR:133.2 (130.7, 135.7), and for Black males, SS:137.0 (133.8, 140.1) vs. SR: 129.6 (127.0, 132.3). On average, SBP increased 1.02 (0.065, 1.98) mmHg with each unit increase in Na/K ratio and 3.30 (2.41, 4.19) mmHg with each 10-year increase in age. After randomization and exposure to increasing levels of sodium, SBP increased in SS subjects on the control diet:125.3 (123.2, 127.3) to 136.8 (134.8, 138.9), an effect that was greater in White vs Black females and in Black vs White males. SBP increased in SS subjects on the DASH diet: 121.4 (118.8, 124.0) to 131.2 (128.7, 133.7), but there were no differences by race and sex. These results suggest that a 5-10 mmHg change in SBP in subjects on a typical American diet and Na/K ratio are good predictors of SSH and that the DASH diet may help to reduce race and sex disparities.

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Abstract P190: Associations of 24-h Urinary Sodium/potassium (Na/K) Ratio with Recommended Intakes of Na and K: The INTERMAP Study

Circulation ◽

10.1161/circ.133.suppl_1.p190 ◽

2016 ◽

Vol 133 (suppl_1) ◽

Author(s):

Toshiyuki Iwahori ◽

Katsuyuki Miura ◽

Hirotsugu Ueshima ◽

Queenie Chan ◽

Nagako Okuda ◽

...

Keyword(s):

Blood Pressure ◽

Gold Standard ◽

International Study ◽

Dietary Sodium ◽

Who Guidelines ◽

Sodium Potassium ◽

Men And Women ◽

Dietary Potassium ◽

Definitive Guideline ◽

Dietary Data

Background: High dietary sodium (Na), low dietary potassium (K) and high dietary sodium/potassium (Na/K) ratio are associated with adverse blood pressure levels and excess risks of cardiovascular diseases. 24-h urine collection is the gold standard for measuring dietary Na, K and Na/K ratio. Recommended levels of Na and K intakes are suggested in WHO guidelines; less than 85 mmol/day for Na; at least 90 mmol/day for K; there is no definitive guideline for Na/K ratio. Objective: Our primary aim was to compare the level of urinary Na/K ratio with the current recommended levels of Na and K intakes suggested in WHO guidelines. Methods: INTERMAP is an international study on associations of multiple dietary variables with blood pressure (BP), based on two timed 24-hr urine collections and dietary data from 4 in-depth 24-h dietary recalls in 4,680 men and women ages 40-59 years in China, Japan, United Kingdom and United States (US). Na/K ratio of 24-hr urine stratified in 1 unit intervals was compared with the current recommended levels of Na and K intakes suggested in WHO guidelines. Na intake was evaluated by urinary Na excretion; K intake by dietary K intake. Results: Thirty-one of the 4,680 INTERMAP participants (0.7%) had urinary Na/K ratio less than 1. The proportions of participants with Na excretion less than 2 g/day (85 mmol/day) among all 4,680 individuals were 77% (n=24), 19% (n=117), and 0.2% (n=11) in those with urinary Na/K ratio less than 1, 1 to 2, and more than 4, respectively. In US samples (n=2,195) the proportions were 88% (n=15), 19% (n=70), and 0.3% (n=6), respectively. The proportions of participants with dietary K intake more than 3.51 g/day (90 mmol/day) among all 4,680 individuals were 71% (n=22), 38% (n=233), and 2.4% (n=111) in those with urinary Na/K ratio less than 1, 1 to 2, and more than 4, respectively. In US samples the proportions were 59% (n=10), 38% (n=138), and 2.1% (n=47), respectively. Conclusions: WHO recommends Na intake less than 85 mmol/day, and K intake more than 90 mmol/day. Urinary Na/K ratio less than 1 is needed to ensure reasonable compliance with these recommendations. Currently, very few people satisfy urinary Na/K ratio less than 1, so population-wide efforts are needed to reduce salt (sodium chloride) and increase K intake.

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INFLUENCE OF DIETARY POTASSIUM AND SODIUM/POTASSIUM MOLAR RATIOS ON THE DEVELOPMENT OF SALT HYPERTENSION

Journal of Experimental Medicine ◽

10.1084/jem.136.2.318 ◽

1972 ◽

Vol 136 (2) ◽

pp. 318-330 ◽

Cited By ~ 140

Author(s):

Lewis K. Dahl ◽

George Leitl ◽

Martha Heine

Keyword(s):

Blood Pressure ◽

Dietary Sodium ◽

Molar Ratio ◽

Molar Ratios ◽

Dietary Potassium ◽

Induced Hypertension ◽

Salt Hypertension ◽

Blood Pressures ◽

Absolute Concentrations ◽

Dietary Sodium Chloride

Among genetically hypertension-prone rats, dietary sodium (chloride) was demonstrably hypertensinogenic and potassium (chloride) antihypertensinogenic. On diets containing the same NaCl but different KCl concentrations, mean blood pressure was greater in rats receiving less dietary potassium, i.e., diets with a higher Na/K molar ratio. On diets with different absolute concentrations of NaCl and KCl, but the same Na/K molar ratios, rats on the higher absolute NaCl intakes had the higher blood pressures. On diets with different absolute concentrations of NaCl and KCl, and different Na/K molar ratios, a group on a lower absolute NaCl intake but with a higher Na/K ratio could have more hypertension than a group on a higher absolute NaCl intake but with a lower Na/K ratio. At equivalent molar ratios, the respective effects of these two ions on blood pressure were dominated by that of sodium. It was concluded that the dietary Na/K molar ratio can be an important determinant for the severity, or even development, of salt-induced hypertension. The mechanism of the moderating effect of potassium on sodium-induced hypertension was unclear.

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Dietary sodium restriction decreases urinary NGAL in older adults with moderately elevated systolic blood pressure free from chronic kidney disease

Journal of Investigative Medicine ◽

10.1136/jim-2020-001343 ◽

2020 ◽

Vol 68 (7) ◽

pp. 1271-1275

Author(s):

Wei Wang ◽

Michel Chonchol ◽

Douglas R Seals ◽

Kristen L Nowak

Keyword(s):

Blood Pressure ◽

Older Adults ◽

Chronic Kidney Disease ◽

Kidney Disease ◽

Systolic Blood Pressure ◽

Dietary Sodium ◽

Sodium Restriction ◽

Tubular Injury ◽

Urinary Creatinine ◽

Elevated Systolic Blood Pressure

Increased aortic stiffness may contribute to kidney damage by transferring excessive flow pulsatility to susceptible renal microvasculature, leading to constriction or vessel loss. We previously demonstrated that 5 weeks of dietary sodium restriction (DSR) reduces large-elastic artery stiffness as well as blood pressure in healthy middle-aged/older adults with moderately elevated systolic blood pressure (SBP) who are free from chronic kidney disease (CKD). We hypothesized that DSR in this cohort would also reduce urinary concentrations of renal tubular injury biomarkers, which predict incident CKD in the general population. We performed a post hoc analysis using stored 24 hours urine samples collected in 13 participants as part of a randomized, double-blind, crossover clinical trial of DSR (low sodium (LS) target: 50 mmol/day; normal sodium (NS) target: 150 mmol/day). Participants were 61±2 (mean±SEM) years (8 M/5 F) with a baseline blood pressure of 139±2/82±2 mm Hg and an estimated glomerular filtration rate of 79±3 mL/min/1.73 m2. Twenty-four hour urinary sodium excretion was reduced from 149±7 to 66±8 mmol/day during week 5. Despite having preserved kidney function, participants had a 31% reduction in urinary neutrophil gelatinase-associated lipocalin concentrations with just 5 weeks of DSR (LS: 2.8±0.6 vs NS: 4.2±0.8 ng/mL, p<0.05). Results were similar when normalized to urinary creatinine (urinary creatinine did not change between conditions). Concentrations of another kidney tubular injury biomarker, kidney injury molecule-1, were below the detectable limit in all but one sample. In conclusion, DSR reduces an established clinical biomarker of kidney tubular damage in adults with moderately elevated SBP who are free from prevalent kidney disease.

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Sodium intake and the effects of isoproterenol and exercise on plasma renin in man

Journal of Applied Physiology ◽

10.1152/jappl.1978.45.6.870 ◽

1978 ◽

Vol 45 (6) ◽

pp. 870-874 ◽

Cited By ~ 8

Author(s):

F. H. Leenen ◽

P. Boer ◽

G. G. Geyskes

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Systolic Blood Pressure ◽

Diastolic Blood Pressure ◽

Sodium Intake ◽

Plasma Renin ◽

Dynamic Exercise ◽

Dietary Sodium ◽

Sodium Restriction ◽

Dietary Sodium Restriction

Changes in heart rate, blood pressure, and plasma renin activity (PRA) were assessed during infusion of increasing doses of isoproterenol and during increasing work loads of dynamic exercise in five normal young men. Studies were performed at three levels of dietary sodium restriction: normal, moderately, and more severely restricted. Isoproterenol induced the expected dose-related increases in heart rate, systolic blood pressure, and PRA and decreases in diastolic blood pressure. Changes in dietary sodium intake affected these changes only to a minor degree. Dynamic exercise also induced the expected work-load-related increases in heart rate, systolic blood pressure, and PRA and decreases in diastolic blood pressure. Also these changes were not significantly affected by changes in dietary sodium intake. Apparently dietary sodium restriction does not sensitize the renin-releasing mechanisms to sympathetic stimulation.

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